The class of polymers of carbon monoxide and olefin(s) has been known in the art for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. Pat. No. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has become of greater interest in part because of the greater availability of the polymers. More recent processes for the production of the linear alternating polymers, now becoming known as polyketones or polyketone polymers, are illustrated by a number of recently published European Patent Applications No. including 121,965, 181,014, 213,671, and 257,633, and by U.S. Pat. No. 4,788,279. The process, now considered broadly conventional, generally involves the use of a catalyst formed from a Group Vlll metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa of less than about 6, preferably less than 2, and a bidentate ligand of phosphorous, arsenic, antimony or nitrogen. The scope of the polymerization process is extensive but, without wishing to be limited, a preferred catalyst composition is formed from a palladium compound, particularly a palladium carboxylate such as palladium acetate, the anion of trifluoroacetic acid or p-toluenesulfonic acid and a bidentate phosphorous ligand such as 1,3-bis(diphenylphosphino)propane or 1,3-bis[di(2-methoxyphenyl)phosphino]propane.
The polyketone polymers have been shown to have a structure of the general type --CO--A-- wherein A is the moiety of ethylenically unsaturated hydrocarbon. By way of specific illustration, a copolymer of carbon monoxide and ethylene will consist of the repeating unit --CO--C.sub.2 H.sub.4 -- and a terpolymer of carbon monoxide, ethylene and propylene will have a random mixture of --CO--C.sub.2 H.sub.4 -- units and --CO--C.sub.3 H.sub.6 -- units along the polymer chain.
Although the properties of the polyketone polymers are desirable for many applications, it is useful on occasion to modify the properties of the polyketone as by functionalization of the polymer. For example, the carbonyl groups of the polyketone polymer are hydrogenated to produce corresponding polyols. Alternatively, an amount of diolefin is introduced into the polymeric chain and the remaining unsaturation, i.e., the unsaturation not employed as the site through which the polymerization takes place, is available for further chemical reaction to introduce other functional groups. In copending U.S. Pat. application Ser. No. 266,189, filed Nov. 2, 1988 there is disclosed a process for employing conjugated dienes as a monomer in the production of linear alternating polymers to produce a linear alternating polymer having pendant vinyl groups. A second copending U.S. Pat. application, Ser. No. 339,783, filed Apr. 18, 1989, discloses products produced when one monomer is an .alpha., .beta.-diene. Such processes do provide structural features to the linear alternating polymers through which additional functionalization can take place. However, the proportion of such dienes incorporated into the polymer chain is rather small so that the degree of functionalization available is rather low. It would be of advantage to provide novel polymers having a higher degree of pendant unsaturation and a process useful in the production of such polymers.